Slow performance on older Mac

What you have is the base model 2017 21.5" iMac that has the glacially slow 5400 RPM HD. In addition, your EtreCheck report shows:

This computer has a hard drive that appears to be failing.

Malware - Malware detected.

Kernel panics - This system has experienced kernel panics. This could be a sign of hardware failure.

To be honest, if this were my machine I would simply replace the computer. It is now considered obsolete meaning it cannot run current versions of Mac OS and Apple considers it Vintage meaning parts are largely unavailable. In short, I would seriously consider replacing the computer. Personally I would take close look at the 2024 M4 Mac mini. For less than $1500 you can have a nicely configured MM (16GB RAM and a 1TB SSD) and a good quality external display. There are many benefits to this route:

• Future proofed for years to come
• Orders of magnitude faster than the 21.5 model
• 1 year warranty
• Eligible for AppleCare
• Able to run all of your current apps

If cash is in short supply take advantage of Apple 12 month no interest financing. Just some thoughts you may not of have thought of.

However if you want to fix the 21.5" you can also buy an external SSD and use that as your start up drive. You can learn how to do this in How to setup an external SSD as your startup disk. This will be less than $1500 by quite a large margin however you still will have an obsolete and vintage Mac.

I wholeheartedly agree with rkaufmann87 on getting a new Mac. Your's is obsolete hardware wise and system wise.

I would recommend a new Mac Mini with 16 GB of RAM and a 1 TB SSD ($999). That with a 3rd party 27" 4K monitor with built-in speakers (from $90 to $350 depending on brand). This would be considerable less than a new similarly configured 24" iMac ($1899).

Just some food for thought.